7i76 Spindle VFD 0-10V question

andypugh
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12 Jul 2017 13:35 #95730 by andypugh

Replied by andypugh on topic 7i76 Spindle VFD 0-10V question

Don't mess with the encoder, that should be right.

You could tweak the VFD scaling, but you will probably find that it can only be exactly right at one speed. The only way to get better than that is probably to set it up under closed-loop control. And, to be honest, it probably isn't critical to have exact speed to 0.1%.

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timmert
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12 Jul 2017 14:15 #95732 by timmert

Replied by timmert on topic 7i76 Spindle VFD 0-10V question

Really appreciate your help Andy. I just made my first part haha
Encoder is working fine. Constact surface speed is working
Stupid question maybe but will the speed difference be a problem for threading?

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andypugh
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12 Jul 2017 15:24 #95736 by andypugh

Replied by andypugh on topic 7i76 Spindle VFD 0-10V question

No, threading (and other spindle-synchronised moves) slave the Z axis to the spindle position. You can even stop the spindle and they stay in synch, as this video demonstrates

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Emco2342
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18 Jul 2023 11:08 #275730 by Emco2342

Replied by Emco2342 on topic 7i76 Spindle VFD 0-10V question

Is there no electrical signal conversion needed to connect the +24V VFD (pin 12) signals to the pin 6 and 8 of TB4 of the 7i76 board?
Somehow I thought the TB4 pins are TTL level only ... (5Volt)

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andypugh
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18 Jul 2023 13:00 #275735 by andypugh

Replied by andypugh on topic 7i76 Spindle VFD 0-10V question

Emco2342 wrote:
Is there no electrical signal conversion needed to connect the +24V VFD (pin 12) signals to the pin 6 and 8 of TB4 of the 7i76 board?

The spindle control pins are effectively solid-state switches. From the manual:

SPINDLE ISOLATED OUTPUTS
The 7I76 provides 2 isolated outputs for use for spindle direction control, and
spindle enable. These outputs are OPTO coupler Darlington transistors. They are all
isolated from one another so can be used for pull up or pull-down individually. They will
switch a maximum of 50 mA at 0 to 100 VDC. The SPINENA output is special as it uses
the same signal that enables the analog output. When the analog output is enabled, the
SPINENA OPTO output is on.

Be aware, though, that they are polarity-sensitive, so should be wired (for example) with 24V to + and then the VFD pin to -. Or, if the VFD is active low, with the VFD pin to + and the - pin to VFD control 0V / common.

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Emco2342
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18 Jul 2023 19:41 #275759 by Emco2342

Replied by Emco2342 on topic 7i76 Spindle VFD 0-10V question

Thanks for confirming.
I'm curious to see where the information you shared, comes from as I didn''t find it yet myself (that shows mainly my incapability of finding specific info on the internet

)

So then I understand why this indeed would work

7I76 TB4 ==> VFD (DANFOSS VLT2800 and others)
1 SPINDLE- ==> ANALOG COMMON VFD 55
2 SPINDLE OUT ==> ANALOG INPUT VFD 53
3 SPINDLE+ ==> 10V OUT VFD 50
4 NC
5 SPINDLE ENA- ==> START VFD 18
6 SPINDLE ENA+ ==> +24V VFD 12
7 SPINDLE DIR- ==> REVERSE VFD 19
8 SPINDLE DIR+ ==> +24V VFD 12

Thanks a lot for confirming

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andypugh
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18 Jul 2023 19:44 #275760 by andypugh

Replied by andypugh on topic 7i76 Spindle VFD 0-10V question

Go to store.mesanet.com
Look up the 7i76
Click the "Specification" link.
There is a link to download the manual.

Or, alternatively, for any Mesa card type the card name and "man" into Google. For example "7i76man"

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Emco2342
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18 Jul 2023 20:41 #275765 by Emco2342

Replied by Emco2342 on topic 7i76 Spindle VFD 0-10V question

Thanks a lot, I finally found it

I must have overlooked it initially

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